The present invention is based on a fuel injection valve.
German Published Patent Application No. 40 26 721 A1 has already disclosed an injection valve that has a thin cup-shaped orifice disk at its downstream end. This orifice disk possesses a flat bottom part having a plurality of spray discharge openings, and a retaining rim projecting out therefrom, thus creating a pot or cup shape. The orifice disk is attached in the region of its bottom part to a valve seat element by way of a peripheral weld seam, while the retaining rim is immovably joined to a valve seat support by welding. In order to prevent the orifice disk from lifting off as a result of the prevailing fuel pressure, the orifice disk must be of sufficient thickness. The thickness of the orifice disk thereby defined creates the disadvantage that the fuel emerging from the spray discharge openings is not optimally atomized into ultrafine fuel droplets, i.e. that ideal fuel conditioning is not achieved.
It has therefore already been proposed in German Patent No. 41 23 692 to provide a support disk in addition to the orifice disk. The support disk possesses a cup-shaped configuration that grips, between its bottom part and the valve seat element, a flat orifice disk that bulges in a domed shape in its central region. The orifice disk is thus easy to manufacture and can be made relatively thin. The disadvantages mentioned above can be overcome with a design of this kind, but the manufacture of two components entails considerable additional effort, the support disk being thicker than the orifice disk. In addition to the additional component, considerable extra material is also necessary. Handling during mounting of the two components is also more difficult than in the case of a single orifice disk.
The fuel injection valve according to the present invention has, in contrast, the advantage that it has an orifice disk which is configured in a particularly simple manner with absolutely no additional need for additional material or components, and which has greater stability and rigidity as compared to known orifice disks of the same thickness. Improved dynamic long-term durability is also achieved. As a result of the features according to the present invention for increasing the rigidity of the orifice disk, it is possible to make the orifice disk thinner than previously, and thus easily to maintain a specific ratio, occurring under certain installation conditions, between the orifice disk thickness and the orifice diameter of the spray discharge openings.
Advantageously, the protrusions are made in the form of crimps that can be produced by stamping on the orifice disk, which constitutes a sheet-metal part. It is advantageous if at least three protrusions are provided, distributed over the circumference.